Human embryonic development is a well-described but poorly understood process. It involves three component processes which are coordinated in time and space: growth, shaping, and patterning. The proposed project uses a model system -- the developing leg of Drosophila melanogaster -- to investigate (1) the cellular mechanisms of shaping and patterning and (2) the coordination of these processes with each other and with growth. Methods include the use of time-lapse cinematography to follow the movements of individual cells, and the use of various mutations that block morphogenesis or growth or that cause abnormal patterning.